In the production of elongated magnetic articles, such as axially leaded diodes, it is beneficial to mechanically convey such articles within a given operation or from one operation to another. Conventionally an elongated article is conveyed in one of two principal modes which are characterized by the orientation of the article with respect to a path in which it is travelling. If such article is oriented with its elongate dimension parallel to the path, it is said to be travelling longitudinally. If the article is oriented with its elongate dimension perpendicular to the path, it is said to be travelling laterally. Each mode of conveying has its separate characteristics and is selected accordingly for a particular application.
In the process treatment of axially leaded diodes within a given operation, it is typically advantageous to convey such diodes in a lateral manner. For example, in a paint drying operation, a chain conveyor moves the diodes laterally in a spaced, parallel relationship through a lengthy oven. For testing and taping diodes, they are typically disposed in a similar manner on the peripheral surface of a wheel. To feed diodes onto such wheels, they are typically suspended in a magnetic bin which maintains the orientation and advances the diodes in a lateral manner.
It is a characteristic of lateral conveying that each article can be treated on an individual and successive basis with the articles loaded to a high density along the path of travel. It is a further characteristic that conveying speeds are slow to permit individual treatment and to maintain the lateral orientation. A problem is that moving articles laterally requires equipment which is expensive, which consumes considerable space, and which is not easily changed with regard to article speed or direction. Because of the slow speed of article travel, however, there is a minimum of wear on equipment or damage to an article, even when the movement of an article is terminated.
Both lateral and longitudinal modes of travel have been used for conveying articles from one operation to another. However, until recent years, it is believed that there has been little mechanical conveying of devices between operations in the electronic industry using either mode of travel. For example, a batch of axially leaded devices, typically has been run through a lead straightener and captured in a container. The container has then been manually carried and emptied into an orienting apparatus such as a magnetic bin which fed the diodes onto a testing wheel. Consequently, in the integration of electronic operations, there appears to be a long felt need for inter-operational conveying without the problems associated with lateral conveying.
In a longitudinal mode of conveying elongated articles, troughs and tubes are often used to support and guide the articles with the motive power typically supplied by the force of gravity or a stream of air. Troughs appear to be used primarily for conveying over short distances or where in-transit treatment is desired, within a given operation. It will be appreciated that tubing offers little such in-transit treatment of articles enclosed therewithin. It will also be appreciated that utilization of the force of gravity is limited by available differences in equipment elevation in a production line.
Fortunately, air-powered tubes are typically quite inexpensive, they consume little space, and are accommodating to changes in speed and direction of article travel. However, if articles are to be delivered for individual and successive treatment, low air pressure is typically used, producing only moderate speeds and low density loading. The problem is that high speeds typically produce almost intolerable terminating conditions. For example, an axially leaded diode has a pair of wire-like leads extending from a generally central, body portion. Such leads are quite susceptible to being bent in the course of terminating a diode travelling longitudinally at high speeds.
Despite the termination problem, high speed, longitudinal conveying of diodes is desirable for special applications. These applications include long distance conveying between operations and short distance recycling of diodes within an operation. For example, in a polarity testing operation, it is desirable to capture a diode of reversed polarity at the output and to return the diode in a reoriented manner to the input of the testing apparatus.
In the long or the short distance applications, it is desirable that a longitudinally oriented diode, travelling at high speeds be decelerated, reoriented, and fed into a lateral conveying apparatus without damage to the article or excessive wear on equipment.